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Wysocki" , Andrew Morton , Stephen Rothwell , Pavel Tatashin , Michal Hocko , Oscar Salvador , Chris von Recklinghausen References: <20190719135244.15242-1-david@redhat.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= mQINBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABtCREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT6JAj4EEwECACgFAljj9eoCGwMFCQlmAYAGCwkI BwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEE3eEPcA/4Na5IIP/3T/FIQMxIfNzZshIq687qgG 8UbspuE/YSUDdv7r5szYTK6KPTlqN8NAcSfheywbuYD9A4ZeSBWD3/NAVUdrCaRP2IvFyELj xoMvfJccbq45BxzgEspg/bVahNbyuBpLBVjVWwRtFCUEXkyazksSv8pdTMAs9IucChvFmmq3 jJ2vlaz9lYt/lxN246fIVceckPMiUveimngvXZw21VOAhfQ+/sofXF8JCFv2mFcBDoa7eYob s0FLpmqFaeNRHAlzMWgSsP80qx5nWWEvRLdKWi533N2vC/EyunN3HcBwVrXH4hxRBMco3jvM m8VKLKao9wKj82qSivUnkPIwsAGNPdFoPbgghCQiBjBe6A75Z2xHFrzo7t1jg7nQfIyNC7ez MZBJ59sqA9EDMEJPlLNIeJmqslXPjmMFnE7Mby/+335WJYDulsRybN+W5rLT5aMvhC6x6POK z55fMNKrMASCzBJum2Fwjf/VnuGRYkhKCqqZ8gJ3OvmR50tInDV2jZ1DQgc3i550T5JDpToh dPBxZocIhzg+MBSRDXcJmHOx/7nQm3iQ6iLuwmXsRC6f5FbFefk9EjuTKcLMvBsEx+2DEx0E UnmJ4hVg7u1PQ+2Oy+Lh/opK/BDiqlQ8Pz2jiXv5xkECvr/3Sv59hlOCZMOaiLTTjtOIU7Tq 7ut6OL64oAq+uQINBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCghCj/CA/lc/LMthqQ773ga uB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseBfDXHA6m4B3mUTWo13nid 0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts6TZ+IrPOwT1hfB4WNC+X 2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiuQmt3yqrmN63V9wzaPhC+ xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKBTccu2AXJXWAE1Xjh6GOC 8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvFFFyAS0Nk1q/7EChPcbRb hJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh2YmnmLRTro6eZ/qYwWkC u8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRkF3TwgucpyPtcpmQtTkWS gDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0LLH63+BrrHasfJzxKXzqg rW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4vq7oFCPsOgwARAQABiQIl BBgBAgAPBQJVy5+RAhsMBQkJZgGAAAoJEE3eEPcA/4NagOsP/jPoIBb/iXVbM+fmSHOjEshl KMwEl/m5iLj3iHnHPVLBUWrXPdS7iQijJA/VLxjnFknhaS60hkUNWexDMxVVP/6lbOrs4bDZ NEWDMktAeqJaFtxackPszlcpRVkAs6Msn9tu8hlvB517pyUgvuD7ZS9gGOMmYwFQDyytpepo YApVV00P0u3AaE0Cj/o71STqGJKZxcVhPaZ+LR+UCBZOyKfEyq+ZN311VpOJZ1IvTExf+S/5 lqnciDtbO3I4Wq0ArLX1gs1q1XlXLaVaA3yVqeC8E7kOchDNinD3hJS4OX0e1gdsx/e6COvy qNg5aL5n0Kl4fcVqM0LdIhsubVs4eiNCa5XMSYpXmVi3HAuFyg9dN+x8thSwI836FoMASwOl C7tHsTjnSGufB+D7F7ZBT61BffNBBIm1KdMxcxqLUVXpBQHHlGkbwI+3Ye+nE6HmZH7IwLwV W+Ajl7oYF+jeKaH4DZFtgLYGLtZ1LDwKPjX7VAsa4Yx7S5+EBAaZGxK510MjIx6SGrZWBrrV TEvdV00F2MnQoeXKzD7O4WFbL55hhyGgfWTHwZ457iN9SgYi1JLPqWkZB0JRXIEtjd4JEQcx +8Umfre0Xt4713VxMygW0PnQt5aSQdMD58jHFxTk092mU+yIHj5LeYgvwSgZN4airXk5yRXl SE+xAvmumFBY Organization: Red Hat GmbH Message-ID: Date: Wed, 27 Nov 2019 17:53:12 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20190719135244.15242-1-david@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-MC-Unique: E91XOfaNMXy8-QgciHXhhQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 19.07.19 15:52, David Hildenbrand wrote: > We don't allow to offline memory block devices that belong to multiple > numa nodes. Therefore, such devices can never get removed. It is > sufficient to process a single node when removing the memory block. No > need to iterate over each and every PFN. >=20 > We already have the nid stored for each memory block. Make sure that > the nid always has a sane value. >=20 > Please note that checking for node_online(nid) is not required. If we > would have a memory block belonging to a node that is no longer offline, > then we would have a BUG in the node offlining code. >=20 > Cc: Greg Kroah-Hartman > Cc: "Rafael J. Wysocki" > Cc: Andrew Morton > Cc: David Hildenbrand > Cc: Stephen Rothwell > Cc: Pavel Tatashin > Cc: Michal Hocko > Cc: Oscar Salvador > Signed-off-by: David Hildenbrand > --- >=20 > v1 -> v2: > - Remove the "mixed nid" part, add a comment instead. Drop the warning. >=20 > --- > drivers/base/memory.c | 1 + > drivers/base/node.c | 39 +++++++++++++++------------------------ > 2 files changed, 16 insertions(+), 24 deletions(-) >=20 > diff --git a/drivers/base/memory.c b/drivers/base/memory.c > index 20c39d1bcef8..154d5d4a0779 100644 > --- a/drivers/base/memory.c > +++ b/drivers/base/memory.c > @@ -674,6 +674,7 @@ static int init_memory_block(struct memory_block **me= mory, > =09mem->state =3D state; > =09start_pfn =3D section_nr_to_pfn(mem->start_section_nr); > =09mem->phys_device =3D arch_get_memory_phys_device(start_pfn); > +=09mem->nid =3D NUMA_NO_NODE; > =20 > =09ret =3D register_memory(mem); > =20 > diff --git a/drivers/base/node.c b/drivers/base/node.c > index 75b7e6f6535b..840c95baa1d8 100644 > --- a/drivers/base/node.c > +++ b/drivers/base/node.c > @@ -759,8 +759,6 @@ static int register_mem_sect_under_node(struct memory= _block *mem_blk, > =09int ret, nid =3D *(int *)arg; > =09unsigned long pfn, sect_start_pfn, sect_end_pfn; > =20 > -=09mem_blk->nid =3D nid; > - > =09sect_start_pfn =3D section_nr_to_pfn(mem_blk->start_section_nr); > =09sect_end_pfn =3D section_nr_to_pfn(mem_blk->end_section_nr); > =09sect_end_pfn +=3D PAGES_PER_SECTION - 1; > @@ -789,6 +787,13 @@ static int register_mem_sect_under_node(struct memor= y_block *mem_blk, > =09=09=09if (page_nid !=3D nid) > =09=09=09=09continue; > =09=09} > + > +=09=09/* > +=09=09 * If this memory block spans multiple nodes, we only indicate > +=09=09 * the last processed node. > +=09=09 */ > +=09=09mem_blk->nid =3D nid; > + > =09=09ret =3D sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj, > =09=09=09=09=09&mem_blk->dev.kobj, > =09=09=09=09=09kobject_name(&mem_blk->dev.kobj)); > @@ -804,32 +809,18 @@ static int register_mem_sect_under_node(struct memo= ry_block *mem_blk, > } > =20 > /* > - * Unregister memory block device under all nodes that it spans. > - * Has to be called with mem_sysfs_mutex held (due to unlinked_nodes). > + * Unregister a memory block device under the node it spans. Memory bloc= ks > + * with multiple nodes cannot be offlined and therefore also never be re= moved. > */ > void unregister_memory_block_under_nodes(struct memory_block *mem_blk) > { > -=09unsigned long pfn, sect_start_pfn, sect_end_pfn; > -=09static nodemask_t unlinked_nodes; > - > -=09nodes_clear(unlinked_nodes); > -=09sect_start_pfn =3D section_nr_to_pfn(mem_blk->start_section_nr); > -=09sect_end_pfn =3D section_nr_to_pfn(mem_blk->end_section_nr); > -=09for (pfn =3D sect_start_pfn; pfn <=3D sect_end_pfn; pfn++) { > -=09=09int nid; > +=09if (mem_blk->nid =3D=3D NUMA_NO_NODE) > +=09=09return; > =20 > -=09=09nid =3D get_nid_for_pfn(pfn); > -=09=09if (nid < 0) > -=09=09=09continue; > -=09=09if (!node_online(nid)) > -=09=09=09continue; > -=09=09if (node_test_and_set(nid, unlinked_nodes)) > -=09=09=09continue; > -=09=09sysfs_remove_link(&node_devices[nid]->dev.kobj, > -=09=09=09 kobject_name(&mem_blk->dev.kobj)); > -=09=09sysfs_remove_link(&mem_blk->dev.kobj, > -=09=09=09 kobject_name(&node_devices[nid]->dev.kobj)); > -=09} > +=09sysfs_remove_link(&node_devices[mem_blk->nid]->dev.kobj, > +=09=09=09 kobject_name(&mem_blk->dev.kobj)); > +=09sysfs_remove_link(&mem_blk->dev.kobj, > +=09=09=09 kobject_name(&node_devices[mem_blk->nid]->dev.kobj)); > } > =20 > int link_mem_sections(int nid, unsigned long start_pfn, unsigned long en= d_pfn) >=20 Just a note that this was actually also a bugfix as noted by Chris. If the memory we are removing was never onlined, get_nid_for_pfn()->pfn_to_nid() will return garbage. Removing will succeed but links will remain in place. Can be triggered by 1. hotplugging a DIMM to node 1 2. not onlining the memory blocks 3. unplugging it 4. re-plugging it to node 1 We will trigger the BUG_ON(ret) in add_memory_resource(), because link_mem_sections() will return with -EEXIST. --=20 Thanks, David / dhildenb